Constructing Cu0/Cu+ interfaces on Cu-based MOF derivatives to promote the adsorption stability of intermediates in the process of CO2 electroreduction to C2 products

Utilizing electrocatalysis to convert CO2 into high-value industrial raw materials can not only effectively reduce CO2 emissions but also achieve a closed carbon cycle. This method holds great potential for addressing global warming and alleviating the fossil fuel crisis. Here, we report a novel electrocatalyst for CO2 reduction composed of a composite material derived from Cu-MOF74 and Cu2O, synthesized under the regulation of an appropriate amount of KOH. The research results indicate that the unique Cu-0/Cu+ interface in Cu-MOF74/Cu2O-350 enhances the adsorption of reaction intermediates, providing more active sites for CO2 reduction. Additionally, the moderate carbonization during the thermal treatment process increases conductivity and enriches the electrochemical active surface area, accelerating the charge transfer rate. Consequently, this composite exhibits excellent CO2 reduction performance. At -1.3 V vs. RHE, the Faraday efficiency (FE) for C2H4 production reached up to 32.48%, which was significantly higher than that of pure Cu2O-350 (9.25%) and Cu-MOF74-350 (15.52%). Even after 6 hours of reaction, the FE for C2H4 remained above 24.52%, reflecting its good stability. Furthermore, we utilized in situ infrared spectroscopy to study the key intermediates of the relevant reduction products, inferring the possible reaction pathways for the formation of HCOOH and C2H4. This study provides a simple synthesis method for the preparation of high-selectivity MOF-derived composite catalysts for the electrocatalytic reduction of CO2 to value-added chemicals.